Language Reference

You can control your program's execution sequence by constructs
containing statement blocks and other executable statements that can alter the
normal execution sequence, as defined under Order of Statements and Execution Sequence. The construct descriptions in this chapter do not
provide detailed syntax of any construct statements; rather, references
are made to the "Statements" section.

If a construct is contained in another construct, it must be wholly
contained (nested) within that construct. If a statement specifies a
construct name, it belongs to that construct; otherwise, it belongs to
the innermost construct in which it appears.